The present invention relates to a central mechanism for a tire vulcanizer, which uses a both-end open type bladder.
A conventional tire vulcanizer is described with reference to FIG. 6. Reference numeral 50 denotes a bladder, 51 denotes a lower ring, 51a denotes an internally threaded portion provided on the lower inside peripheral surface of the lower ring 51, and 52 denotes a lower bead ring fixed to the lower ring 51. The lower part of the bladder 50 is held by the lower ring 51 and the lower bead ring 52.
Reference numeral 53 denotes a housing, 53a denotes an externally threaded portion provided on the upper outside peripheral surface of the housing 53, and 54 denotes O-ring grooves provided on the aforementioned outside peripheral surface of the housing 53. The externally threaded portion 53a provided on the upper outside peripheral surface of the housing 53 is threadedly engaged with the internally threaded portion 51a provided on the lower inside peripheral surface of the lower ring 51, so that the housing 53 is detachably fixed to the lower ring 51.
A post 55 is provided in the housing 53 in such a manner as to be capable of moving vertically. At the upper part of the post 55 are provided an upper ring (not shown) for holding the upper part of the bladder 50 and an upper clamp ring (not shown). The upper ring and the post 55 are bolted to each other, and the lower end of the post 55 is connected to a piston of a fluid pressure cylinder, so that when the fluid pressure cylinder is operated in the extending direction, a bladder assembly (a bladder assembly consisting of the bladder 50, the lower ring 51, the lower bead ring 52, the upper ring, and the upper clamp ring) is elevated.
At this time, the lower ring 51 is rotated about five to six turns together with the bladder 50 by man power so that the lower ring 51 is removed from the housing 53, by which the bladder 50 and the O-rings in the O-ring grooves 54, which are expendables, are replaced.
On the conventional tire vulcanizer shown in FIG. 6, when the bladder 50 and the O-rings are replaced, an operator must remove the housing 53 by rotating the lower ring 51 about five to six turns together with the bladder 50 in a high-temperature atmosphere. Therefore, not only the replacement of the bladder 50 and O-rings requires much time, but also hard work is forced upon the operator in a high-temperature atmosphere, which imposes an excessive burden on the operator.
Also, since the replacement of the bladder 50 and O-rings requires much time as described above, the productivity is decreased, and radiation loss is increased.
To overcome these problems, the applicant of this invention has already proposed a tire vulcanizer shown in FIGS. 7 and 8 (Japanese Patent Provisional Publication No. 01-047511 (047511/1989)).
With this tire vulcanizer, after the vulcanization of a tire is completed, a piston rod 136a of a fluid pressure cylinder 136 is operated in the extending direction to turn a Y-shaped lever 133 clockwise around a rotation axis 132, by which a lever 135 and a fluid pressure cylinder 123, and a housing 115, a piston rod 123a, a rod 116, a bladder assembly 105 to 113, and each vulcanizing medium inflow/outflow pipe 114 are elevated to separate a lower bead ring 110 of the bladder assembly 105 to 113 from a lower mold 104.
Next, piston rod 139a of a fluid pressure cylinder 139 for each stopper 141 is operated in the extending direction to move each stopper 141 to a position just under each nut 127.
Then, the piston rod 136a of the fluid pressure cylinder 136 is operated in the retracting direction to turn the Y-shaped lever 133 counterclockwise around the rotation axis 132, by which the lever 135 and the fluid pressure cylinder 123, and the housing 115, the piston rod 123a, the rod 116, the bladder assembly 105 to 113, and each vulcanizing medium inflow/outflow pipe 114 are lowered to make each nut 127 abut against each stopper 141.
At this time, the lowering of each vulcanizing medium inflow/outflow pipe 114 and the bladder assembly 105 to 113 ceases, but the lowering of other parts, that is, the lever 135 and the fluid pressure cylinder 123, and the housing 115 and the bladder assembly 105 to 113 continues. Therefore, each belleville spring 128 is pressed by a flange 123c of the fluid pressure cylinder 123, and a head 114a of the vulcanizing medium inflow/outflow pipe 114 is separated from an engagement hole 109a formed in a lower ring 109 of the bladder assembly 105 to 113.
When this state is reached, a bolt 126, which detachably fixes an upper ring 106 of the bladder assembly 105 to 113 to a rod 116, is removed.
Then, the bladder assembly 105 to 113 is rotated in the direction of arrow (F) (counterclockwise) in FIG. 8 in the range of the engagement hole 109a around the center axis of the tire vulcanizer by man power, so that the head 114a of each vulcanizing medium inflow/outflow pipe 114 is positioned at the large-diameter hole portion of the engagement hole 109a. Reference character L in FIG. 8 denotes a lock position, and UL denotes an unlock position.
Next, the bladder assembly 105 to 113 is pulled out upward.
After the old bladder is replaced with a new one, the bladder assembly 105 is mounted by reversing the above procedure, by which the preparation for tire vulcanization is completed.
On this tire vulcanizer, although the amount of rotation is significantly reduced, the lower ring must be rotated together with the bladder. Therefore, the frictional resistance of O-ring, which is inserted between the lower ring and the housing, is high, so that there remains a problem of hard work being forced upon the operator in a high-temperature atmosphere.
The present invention was made to solve the above problems. Accordingly, an object of the present invention is to provide a central mechanism for a tire vulcanizer, which can significantly shorten the work time for replacing a bladder, which is an expendable.
To achieve the above object, the present invention provides a central mechanism for a tire vulcanizer, which uses a both-end open type bladder, comprising: a plurality of clamp rods slidably inserted into a housing to the lower part of which a post cylinder for vertically expanding and contracting a bladder assembly is assembled; a claw mechanism for detachably engaging the upper end portion of the clamp rod with the lower ring of the bladder assembly; and driving means for vertically moving and turning the clamp rod.
The central mechanism for a tire vulcanizer in accordance with the present invention, which is constructed as described above, is operated as described below. After a tire has been vulcanized (a bladder is expanded), the clamp rod is elevated to elevate a lower ring and separate it from the housing. After that, the clamp rod is turned so that a claw of the claw mechanism between the lower ring and the clamp rod can pass through. Then, a pin fixing a post to an upper ring is pulled out, and the bladder assembly is hung and carried out of the vulcanizer to replace the bladder and O-rings. After the bladder and other parts have been replaced, the bladder assembly is hung and mounted to the vulcanizer so that the hole for the claw mechanism of the lower ring is aligned with the upper end of the clamp rod. At this time, when the claw of the claw mechanism passes through, the lower ring is supported by the elevated clamp rod, and the lower ring and a supply/discharge opening of the housing is aligned with each other. After the mounting of the bladder assembly is completed, the pin is inserted in the upper ring and the post by reversing the above procedure to connect them to each other. The clamp rod is turned in the reverse direction to engage the claw of the claw mechanism. Then, the clamp rod is lowered to seat the lower ring on the housing, by which the preparation for vulcanizing tire is completed.
In a central mechanism for a tire vulcanizer in accordance with the present invention, after a tire has been vulcanized (a bladder is expanded), the clamp rod is elevated to elevate the lower ring and separate it from the housing. After that, the clamp rod is turned so that the claw of the claw mechanism between the lower ring and the clamp rod can pass through. Then, the pin fixing the post to the upper ring is pulled out, and the bladder assembly is hung and carried out of the vulcanizer to replace the bladder and O-rings. After the bladder and other parts have been replaced, the bladder assembly is hung and mounted to the vulcanizer so that the hole for the claw mechanism of the lower ring is aligned with the upper end of the clamp rod. At this time, when the claw of the claw mechanism passes through, the lower ring is supported by the elevated clamp rod, and the lower ring and a supply/discharge opening of the housing is aligned with each other. After the mounting of the bladder assembly is completed, the pin is inserted in the upper ring and the post by reversing the above procedure to connect them to each other. The clamp rod is turned in the reverse direction to engage the claw of the claw mechanism. Then, the clamp rod is lowered to seat the lower ring on the housing, by which the preparation for vulcanizing tire is completed. Therefore, when the bladder and other parts are replaced, the manual work which must be done by the operator is only the insertion and withdrawal of the pin fixing the post to the upper ring and the attachment and removal of lifting equipment, so that the manual turning work of the lower ring, which has so far been most dangerous and required much time, can be eliminated. Thereupon, the work time for replacing a bladder, which is an expendable, can be shortened significantly.